Mitsuba is a research-oriented rendering system in the style of PBRT, from which it derives much inspiration. It is written in portable C++, implements unbiased as well as biased techniques, and contains heavy optimizations targeted towards current CPU architectures.

Some major publications:

We present an integral equation which generalizes a variety of known rendering algorithms.
[…]
We mention that the idea behind the rendering equation is hardly new.
[…]
However, the form in which we present this equation is well suited for computer graphics, and we believe that this form has not appeared before.

The basic idea is that particles are shot at the same time from a selected light source and from the viewing point, in much the same way. All hit points on respective particle paths are then connected using shadow rays and the appropriate contributions are added to the flux of pixel in question.

Our statistical contributions include a new technique called multiple importance sampling, which can greatly increase the robustness of Monte Carlo integration. It uses more than one sampling technique to evaluate an integral, and then combines these samples in a way that is provably close to optimal. This leads to estimators that have low variance for a broad class of integrands. We also describe a new variance reduction technique called efficiency-optimized Russian roulette.

[…]

The second algorithm we describe is Metropolis light transport, inspired by the Metropolis sampling method from computational physics. Paths are generated by following a random walk through path space, such that the probability density of visiting each path is proportional to the contribution it makes to the ideal image.

Nathan Reed recently published a blog article plotting his numerical findings of Z-buffer precision under different uses. On the way he references a couple of previous articles, that also reference other resources; I think it’s a good opportunity to list some of them. They all tell a part of the story and I recommend reading all of them to get the complete picture.

The Game Developers Conference took place last week in San Francisco. As I am starting to see more speakers publish their slides, I am creating this post to keep track of some them (this list is not meant to be exhaustive).

The Art of Rendering (April 2012)
A description of the different techniques used in high end rendering and the major engines.

The State of Rendering (July 2013): part 1, part 2
A lengthy overview of the state of the art in high end rendering, comparing the different tools and rendering solutions available, their approach and design choices, strengths and weaknesses as well as the consequences in terms of quality, scalability and render time.